Well, RPGs came out of board game terminology, to distinguish them from say, Scrabble or Snakes and Ladders. In video games, you can’t really say you’re trying to understand who Mario really is, he’s just a game piece in a video game, like pac man. Likewise, when you’re playing a sports video game, you’re trying to win the sports match. What distinguishes the primary RPG mechanic from any other kind of game is that it’s not you the player that has to become good at the thing, but the character will become better at the thing, leaving the focus on the game on experiencing that character’s life, whether it’s a JRPG hallway simulator or a procedurally-generated open world or the adventure you tell with your friends during a game of D&D. The goal is to get you invested in the character and their journey, whether it’s the character writing of the Witcher or the TTRPG/MMORPG character you write yourself.
Of course, investing in the characters turns out to be a great way to get players invested in your games, so most games now have Upgrade/Level-Up features but that doesn’t make them RPGs. Ori and the Blind Forest has a skill tree that unlocks new abilities, but the core goal of the game is still to jump around and solve puzzles, not immerse yourself in Ori’s lived experience — this is despite the great care the game takes to give you an emotional investment in the few but precious story scenes. I’m sure lots of shooters now have Level-Up options to (as opposed to classic shooters like Goldeneye or Duckhunt) but games like Horizon Zero Dawn cross the line into “Action” RPG because the focus of the game is on Aloy’s lived experience and who she is, rather than a Call of Duty which is essentially an interactive action movie.
...FUCK ME, I have to do Chapter 9 AGAIN just to get the last two manuscripts. God fucking damnit. I have now played through Chapters 3, 8, and 9 FOUR TIMES EACH. Is this what gamers call “endgame content”? I’m still stuck in the 90s apparently, because this is tedious as fuck.